Quick-release adhesive tapes

ABSTRACT

Methods and compositions for securing to and removing adhesive tapes from substrates, e.g., delicate substrates such as skin, are described. The methods include providing an adhesive tape comprising an adhesive layer and a support layer in contact with the adhesive layer. A first adhesion level between the adhesive layer and the support layer is, or can be controlled to be, less than a second adhesion level between the adhesive layer and the substrate. The methods further include applying the adhesive tape to the substrate by contacting the adhesive layer to the substrate while the support layer remains in contact with the adhesive layer; and removing the support layer from the substrate by separating the support layer from the adhesive layer.

CLAIM OF PRIORITY

This application is a U.S. National Phase Application under 35 U.S.C. §371 of International Patent Application No. PCT/US2013/044558, filed onJun. 6, 2013, which claims priority to U.S. Provisional Application Ser.No. 61/656,639, filed on Jun. 7, 2012, the entire contents of which arehereby incorporated by reference.

STATEMENT AS TO FEDERALLY SPONSORED RESEARCH

This invention was made with Government support under Grant No. 106430awarded by Philips Fund; and the National Institutes of Health Grant No.NIH OSP#6921553 NIH-DE013023. The Government has certain rights in theinvention.

FIELD OF THE INVENTION

The invention relates to medical and other adhesive tapes.

BACKGROUND OF THE INVENTION

Medical adhesive removal causes more than 1.5 million injuries each yearin the US alone. Neonatal skin lacks an epidermis, making it highlysensitive and prone to damage during adhesive tape removal. Injuries dueto adhesive tape removal from neonates include skin irritation,permanent scarring, and lifelong restrictions of motion resulting, forinstance, from fibrosis, which can occur near joints or other dynamictissues injured by the removal of adhesive tapes. The removal of medicaladhesive tapes is also dangerous to elderly subjects, whose skin isoften thin and loosely anchored.

FIGS. 1A-1B show a conventional medical tape 100 affixed to skin 102,such as the sensitive skin of a neonate. Tape 100 is a bilayer tape thatincludes an adhesive 104 supported on a backing 106. When tape 100 isremoved, portions of skin 102 remain attached to adhesive 104 and may beremoved along with the tape; other portions of adhesive 104 stay on theskin as residual adhesive 108.

SUMMARY OF THE INVENTION

The invention is based, at least in part, on the discovery thatquick-release tapes that have an adhesive layer and a support layer,arranged such that the support layer can be easily removed from theadhesive layer, can be quickly and easily removed from a substrate(e.g., delicate substrates such as skin, e.g., in elderly or neonatalsubjects) without damaging the substrate, e.g., the skin, while all ormost of the adhesive remains on the substrate. Removal of the supportlayer can be achieved, for instance, by causing the adhesion between theadhesive layer and the support layer to be less than the adhesionbetween the adhesive layer and the substrate.

In a general aspect, methods for securing to and removing from asubstrate, e.g., skin, such as delicate skin, an adhesive tape includesproviding an adhesive tape comprising an adhesive layer and a supportlayer in contact with the adhesive layer. A first adhesion level betweenthe adhesive layer and the support layer is less than a second adhesionlevel between the adhesive layer and the substrate. The methods furtherinclude applying the adhesive tape to the substrate by contacting theadhesive layer to the substrate while the support layer remains incontact with the adhesive layer; and removing the adhesive tape byremoving the support layer from the substrate by separating the supportlayer from the adhesive layer, and leaving the adhesive layer behind onthe substrate.

In various implementations, these methods include one or more of thefollowing features.

The first adhesion level is controlled during manufacture of theadhesive tape, and removing the support layer from the substrateincludes peeling the support layer away from the adhesive layer.

Removing the support layer from the substrate includes controlling thefirst adhesion level to reduce the first adhesion level to be less thanthe second adhesion level and then peeling the support layer from theadhesive layer.

Removing the support layer from the substrate includes removing thesupport layer without damaging the substrate.

Removing the support layer from the substrate causes a device fixationshear adhesion characteristic of the adhesive tape to be reduced by atleast about 25%, e.g., 50% or 75%.

Removing the support layer from the substrate includes applying a normalforce to an interface between the support layer and the adhesive layer.

The adhesive layer can adhere to the substrate without removal of thesupport layer.

The support layer includes a backing, and a release agent layer disposedbetween the backing and the adhesive layer. The first adhesion levelbetween the adhesive layer and the support layer is altered by astructural characteristic of the release agent layer. The structuralcharacteristic includes discontinuities in the release agent layer. Thestructural characteristic includes a percent area of the backing that isexposed to the adhesive layer. A third adhesion level between theadhesive layer and the release agent layer is less than the secondadhesion level between the adhesive layer and the substrate.

A force sufficient to separate the support layer from the adhesive layeris at least 10%, 50%, or 90% less than a force sufficient to remove atleast a portion of the adhesive layer from the substrate.

Removing the support layer from the substrate includes leaving at least75% or 90% of the adhesive layer on the substrate.

The methods further include causing the adhesive layer that remains onthe substrate after removal of the adhesive tape to be de-tackified.Causing the adhesive layer to be de-tackified includes coating theadhesive layer with a powder. The method further includes adhering asecond tape to the de-tackified adhesive layer.

Applying the adhesive tape to the substrate includes affixing a medicaldevice to the substrate.

In another general aspect, quick-release tapes include a support layer,including a backing, and a patterned release agent layer disposed on thebacking layer. The quick-release tapes also include an adhesive layerdisposed on the release agent layer.

In various implementations, these tapes can include one or more of thefollowing features.

The adhesive layer is configured to be disposed on a substrate. A firstadhesion level between the adhesive layer and the substrate is greaterthan a second adhesion level between the adhesive layer and the supportlayer.

An adhesion level between the adhesive layer and the release agent layeris a function of an angle of a force applied to an interface between theadhesive layer and the release agent layer.

The patterned release agent layer can be patterned with an irregularpattern.

The release agent layer includes first domains and second domains. Afirst adhesion level between the first domains and the adhesive layer isdifferent from a second adhesion level between the second domains andthe adhesive layer. An adhesion level between the adhesive layer and thesupport layer is a function of a fraction of the release agent layercomposed of the first domains. The adhesive layer is in contact with thebacking in the first domains.

An adhesion level between the adhesive layer and the support layer is afunction of a percent area of the backing that is exposed to theadhesive layer.

The release layer can be discontinuous.

The backing is formed of a first backing material having a firststiffness and a second backing material having a second stiffness lessthan the first stiffness.

The tapes further include a cover layer disposed on the adhesive layer.A first adhesion level between the cover layer and the support layer isless than a second adhesion level between the adhesive layer and thesupport layer.

The backing forms part of a medical device.

A first image is formed on the support layer. A second image is formedon the adhesive layer.

In another general aspect, methods for making a tape include forming asupport layer by disposing a release agent layer onto a backing layer,and patterning the release agent layer. The methods also includedisposing an adhesive layer onto the patterned release agent layer suchthat at least a portion of the adhesive layer contacts the backinglayer.

In various implementations, these methods can include one or more of thefollowing features.

Patterning the release agent layer includes removing a portion of therelease agent layer. An adhesion level between the adhesive layer andthe support layer is a function of a fraction of the release agent layerthat is removed.

Patterning the release agent layer includes etching the release agentlayer.

Patterning the release agent layer includes mechanically abrading therelease agent layer.

Patterning the release agent layer includes forming first domains andsecond domains in the release agent layer. A first adhesion levelbetween the first domains and the adhesive layer is different from asecond adhesion level between the second domains and the adhesive layer.An adhesion between the adhesive layer and the support layer is afunction of a fraction of the release agent layer composed of the firstdomains.

In another general aspect, quick-release tapes include a support layer,including a backing, and a release agent layer disposed on the backinglayer. The tapes include an adhesive layer disposed on the release agentlayer, and the release layer is formed of a material having an adhesionlevel that changes in response to a stimulus.

In various implementations, these tapes can include one or more of thefollowing features.

The stimulus is an enzyme and the release agent layer includes amaterial that degrades in the presence of an enzyme.

The release agent layer includes a pH sensitive material and wherein thestimulus is the presence of a solution of a pH sufficient to dissolvethe release agent layer.

The release agent layer includes a photodegradable material and whereinthe stimulus is the presence of light.

The release agent layer includes a material that swells in response tothe stimulus.

The release agent layer includes a shape memory material.

The adhesive layer is configured to be disposed on a substrate, whereina first adhesion level between the adhesive layer and the substrate isgreater than a second adhesion level between the adhesive layer and thesupport layer.

In another general aspect, quick release tapes include a support layer,including a backing, and a release agent layer disposed on the backinglayer. The release agent layer includes a release modifying agent. Thetapes include an adhesive layer disposed on the release agent layer.

In an embodiment, the release modifying agent can include a siloxaneresin.

The quick-release tapes described herein have and provide a number ofadvantages. For instance, the tapes can be used to securely affix adevice, such as a medical device, to a substrate, such as skin. Thetapes securely retain the device and then, when desired, allow thedevice to be removed quickly, easily, and without damage to theunderlying skin. Residual adhesive left on the skin after tape removalcan be easily detackified, mitigating any risk that may have beenpresented by allowing adhesive to remain on the skin. In general, thequick-release tapes described herein are suitable for use in situationswith a need for a strong adhesive, yet easily removable tape, such asfor use with neonatal subjects, geriatric subjects, or other subjectswith sensitive and/or delicate skin. In addition, a wide range ofbacking materials, release layers, and adhesives can be used to form thequick-release tapes, thus enabling the mechanical and biocompatibilitycharacteristics of the tape to be engineered to suit a diverse array ofsituations. Furthermore, the quick-release tapes can be fabricated usingscalable processes that are compatible with industrial infrastructureand processing.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although methods and materialssimilar or equivalent to those described herein can be used in thepractice or testing of the present invention, suitable methods andmaterials are described below. All publications, patent applications,patents, and other references mentioned herein are incorporated byreference in their entirety. In case of conflict, the presentspecification, including definitions, will control. In addition, thematerials, methods, and examples are illustrative only and not intendedto be limiting.

Other features and advantages of the invention will be apparent from thefollowing detailed description, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a schematic diagram of a conventional medical tape affixed toa portion of skin.

FIG. 1B is a schematic diagram of the portion of skin of FIG. 1A afterremoval of the conventional medical tape.

FIG. 2A is a schematic diagram of a quick-release tape affixed to aportion of skin.

FIG. 2B is a schematic diagram of the portion of skin of FIG. 2A afterremoval of the quick-release tape.

FIG. 3 is a cross-sectional view of a quick-release tape.

FIGS. 4A-4B are three-dimensional (3D) and two-dimensional (2D)profiles, respectively, of laser-etched lines in a release agent layerof a quick-release tape.

FIGS. 4C-4D are 3D and 2D optical profiles, respectively, oflaser-etched grid lines, of laser-etched lines in a release agent layerof a quick-release tape.

FIG. 5 is a 3D optical profile of a release agent layer roughened by 400grit sandpaper.

FIG. 6 is a schematic view of an example of a method of making aquick-release tape.

FIGS. 7A-7B are schematic diagrams of residual adhesive remaining on aportion of skin after removal of a support layer and after fouling withtalcum powder, respectively.

FIG. 8A is a schematic diagram of a quick-release tape affixing anendotracheal (ET) tube to a portion of skin.

FIG. 8B is a schematic diagram of the portion of skin of FIG. 8A afterremoval of the backing of the quick-release tape.

FIG. 8C is a schematic diagram of the portion of skin of FIG. 8B afterremoval of the ET tube.

FIG. 9 is a schematic diagram of a roll of quick-release tape.

FIGS. 10A-10B are schematic diagrams of a quick-release tape includingmultiple images.

FIGS. 11A-11B are elemental analyses of the grid patterned release agentlayer of FIG. 4B performed by energy-dispersive spectroscopy analysis.

FIGS. 12A and 12B are photographs of the experimental setup and results,respectively, of a peel test of tapes from a paper substrate.

FIG. 13A is a schematic diagram of an experimental setup for a 90 degreepeel test of various types of tapes from a stainless steel substrate.

FIGS. 13B and 13C are plots of the average peel force and maximum peelforce, respectively, for the stainless steel peel test of FIG. 13A.

FIG. 14A is a photograph of an experimental setup for a 90 degree peeltest of tape from medial ventral forearm skin.

FIGS. 14B and 14C are plots of the average peel force and maximum peelforce, respectively, for the forearm peel test of FIG. 14A.

FIG. 15A is a schematic diagram of an experimental setup for a 90 degreepeel test from a substrate coated with an acrylic-based adhesive.

FIGS. 15B and 15C are plots of the average peel force and maximum peelforce, respectively, for the peel test of FIG. 15A.

FIGS. 16A and 16B are plots of the average peel force and maximum peelforce, respectively, as a function of the spacing of laser-etched linesin the release agent layer of a quick-release tape.

FIGS. 17A and 17B are plots of the average peel force and maximum peelforce, respectively, as a function of the spacing of laser-etched gridlines in the release agent layer of a quick-release tape.

FIG. 17C is a plot of the average crack velocity as a function of timefor crack propagation in different regions of a quick-release tape.

FIGS. 18A and 18B are plots of the average peel force and maximum peelforce, respectively, as a function of the grit of sand paper used toroughen the release agent layer of a quick-release tape.

FIG. 19A is a schematic diagram of an experimental setup for a shearforce test of an endotracheal (ET) tube attached to a substrate withquick-release tape.

FIG. 19B is a plot of the results of the shear force test of FIG. 19A.

FIG. 20A is a schematic diagram of an experimental setup for a 90 degreepeel test of an ET tube attached to a substrate with quick-release tape.

FIG. 20B is a plot of the results of the peel test of FIG. 20A.

FIG. 21A is a schematic diagram of an experimental setup for a probetack test.

FIG. 21B is a plot of the results of a probe tack test on residualadhesive and talcum powder fouled residual adhesive.

FIG. 21C is a plot of the results of a probe tack test on fouled, washedresidual adhesive.

FIG. 21D is a plot of the residual adhesive mass per area after removalof the backing of a quick-release tape.

FIG. 22 is a plot of the average peel force and maximum peel force,respectively, for alternative backings for a quick-release tape.

DETAILED DESCRIPTION

As shown in FIGS. 2A and 2B, an example of one embodiment of the newquick-release tapes 200 can be quickly and easily removed from asubstrate 202 (e.g., skin) without damaging the substrate. Such a tapeis useful, for instance, for affixing medical devices to subjects withdelicate and/or sensitive skin, such as neonatal subjects, children, andelderly or geriatric subjects. Tape 200 includes an adhesive layer 204and a support layer 206, arranged such that support layer 206 can bequickly and easily removed while leaving substantially all of adhesivelayer 204 on substrate 202 (FIG. 2B). When tape 200 is used to affix adevice to substrate 202, the device is strongly secured to thesubstrate. However, upon removal of support layer 206, the affixeddevice can be removed quickly and without damage to the substrate.Residual adhesive that remains on substrate 202 after removal of supportlayer 206 can be detackified by applying a powder, e.g., talcum powder,to the adhesive. Other tapes, including conventional tapes andquick-release tapes, can adhere to washed, talc-fouled residualadhesive, allowing another device to be affixed in a similar position asthe previously removed device.

Support layer 206 can be easily removed from the adhesive layer bycausing the adhesion between adhesive layer 204 and support layer 206(e.g., the tendency of the adhesive layer to stick to the support layer,where the adhesion level is the degree of adhesion between the twolayers) to be less than the adhesion between adhesive layer 204 andsubstrate 202. For instance, in some embodiments, support layer 206includes two sub-layers: a backing 208 and a release agent layer 210.Backing 208 generally provides tape 200 with the majority of itscohesive mechanical strength; decoupling backing 208 from adhesive layer204 prior to tape removal enables easy removal of support layer 206. Oneapproach to decouple or separate backing 208 from adhesive layer 204 isto micro-pattern release agent layer 210. Because the surface area ofinteraction between backing 208 and adhesive layer 204 correlates withthe peel force required to separate support layer 206 from adhesivelayer 204, selective removal of portions of release agent layer 210 canbe used to tune the adhesion between support layer 206 and adhesivelayer 204 in a controllable, predictable manner, without sacrificingdevice fixation integrity.

General Structure of the Quick-Release Tapes

FIG. 3 illustrates an example of a quick-release tape 200 that includesan adhesive layer and a support layer 206. Support layer 206 is formedof a backing 208, which provides cohesive mechanical strength to tape200; and a release agent layer 210, which allows for easy removal ofsupport layer 206 from adhesive layer 204. Adhesive layer 204 isgenerally about 50 μm thick (e.g., 5, 25, or 1,000 μm); backing 208 isgenerally at least 50 μm thick (e.g., 10, 100, or 1,000 μm), and isgenerally thicker than the adhesive layer. Release agent layer 210 has athickness ranging from about 0.5 μm to about 0.8 μm (e.g., 0.1, 50, or750 μm).

The release agent layer can be designed so that the adhesion betweenadhesive layer 204 and release agent layer 210 is greater than theadhesion between release agent layer 210 and substrate 202. One of theways in which this can be achieved is by micro-patterning the releaseagent layer. In other embodiments, the release agent layer can be madeto dissolve or otherwise change so that it adheres less strongly to thesupport layer or completely disappears, allowing the adhesive layer toseparate from the support layer.

Micro-patterning of release agent layer 210 removes material from therelease agent layer, creating gaps 300. In some cases, themicro-patterned release agent layer is continuous (e.g., anuninterrupted pathway exists from one point in the release agent layerto any other point in the release agent layer). In other cases, themicro-patterned release agent layer is discontinuous (e.g., anuninterrupted pathway does not exist from one point in the release agentlayer to at least one other point in the release agent layer). Becauseadhesive layer 204 is formed of a viscous, pressure-sensitive adhesive,once adhesive layer 204 is disposed onto release agent layer 210, asdescribed below, adhesive flows into gaps 300 and comes into contactwith backing 208.

FIGS. 4A-4D show other embodiments, in which a regular pattern of gapsis formed by laser etching a pattern into release agent layer 210. Inone example, a series of lines 400 is patterned into release agent layer210, forming grooves 402, e.g., 15 μm deep, V-shaped grooves, betweenthe lines (FIGS. 4A-4B). On either side of each groove 402 is a mound404, e.g., approximately 10-15 μm in height, created by the settling ofresidue from the laser etching process and from a slight curvature ofthe release agent layer induced by laser etching. In another example,0.5 μm spaced grid lines are laser etched into release agent layer 210,forming 250 μm by 250 μm islands 406 of release agent layer materialseparated by V-shaped grooves 408 (FIGS. 4C-4D). Mounds 410 form alongthe edges of islands 406.

FIG. 5 shows other embodiments, in which an irregular pattern of gaps isformed by mechanical abrasion (e.g., with sandpaper) of release agentlayer 210. In the example shown, 400 grit sandpaper was used to roughenrelease agent layer 210, creating micro-scale divots in the releaseagent layer.

The percent area of backing 208 exposed to adhesive layer 204 (i.e., theareal fraction of release agent layer 210 occupied by gaps 300) controlsthe adhesion between adhesive layer 204 and support layer 206, asdiscussion in greater detail below. For laser etched lines in releaseagent layer 210, the percent area of exposed backing (x_(lines)) iscalculated as the ratio of the width (w) of the lines to the spacing (W)of the lines. The length of the line equals the width of the backing,and thus cancels, leaving the following expression for x_(lines):

$x_{lines} = \frac{w}{W}$A similar expression can be developed for laser etched square gridlines. In particular, the percent area of exposed backing(x_(grid lines)) can be calculated for the smallest repeat unit in thepattern (i.e., a square) and then generalized via symmetryconsiderations. Each square has an exposed backing area of twice thewidth of the laser etched line multiplied by the center-to-center linespacing minus the overlapping portion of the lines at the corners of thesquares, normalized by the area of the square repeat unit:

$x_{{grid}\mspace{11mu}{lines}} = \frac{{2\;{wW}} - w^{2}}{W^{2}}$Geometry of the micro-patterned release layer thus dictates the adhesionbetween adhesive layer 204 and support layer 206, enabling fine tuningof the mechanical properties of the quick-release tapes, as discussed ingreater detail below.

In other embodiments, and as described in more detail below, the releaseagent layer is not patterned, but is made of one or materials that canbe altered when it is time to remove the quick-release tape.

In some embodiments, the quick-release tape is incorporated into adevice, such as a medical device. In these cases, the backing 208 may beattached to the device, e.g., by gluing or otherwise adhering thebacking to the device. Alternatively, the backing 208 may be an integralpart of the device.

Composition and Fabrication of the Quick-Release Tapes

Referring to FIG. 6, to fabricate quick-release tapes 200, a thin layerof release agent layer 210 is coated onto backing 208 (step 600), forinstance, via gravure roll coating. In the examples described below,backing 208 is formed of 50 μm thick polyethylene terephthalate (PET);however, any suitable backing material having sufficient cohesivemechanical strength and appropriate biocompatibility characteristics canbe used. For a quick-release tape with strong adhesion properties,backing 208 may be formed of a stiff material, such as polyethyleneterephthalate, polyethylene, or paper. For a quick-release tape havingadhesive flexibility and/or shock absorption properties, backing 208 maybe formed of a flexible or extensible material, such as elastomersincluding, e.g., polydimethyl siloxane, polyurethanes, ethylene vinylacetate, or butyl rubber. For instance, a flexible or extensible backinghaving shock absorption properties may be capable of, e.g., absorbingforces applied to a device fixed by the tape while preventing detachmentof the device from the substrate, or preventing damage to the underlyingsubstrate or adhesive tape, or improving comfort while the adhesive isfixed to tissue or during removal In some examples, for instance toachieve a quick-release tape that has both strong adhesion andflexibility, backing 208 may be formed of a combination of stiff andflexible materials. For instance, backing 208 may include a stiffmaterial in a central region and a flexible material along the edges ofthe backing.

Release agent layer 210 is micro-patterned (step 602) to achieve adesired percent area of exposed backing, and hence a target adhesionbetween adhesive layer 204 and support layer 206. Micro-patterning therelease layer opens gaps in the release layer to selectively exposeportions of backing, such that when the adhesive layer 204 is positionedon the release layer, the viscous pressure sensitive adhesive flows intothe gaps and contacts backing 208.

In one embodiment, laser etching is used to selectively etch the releaseagent layer material to form the desired pattern (for instance, thelines or grid lines in the images of FIGS. 4A-4D). Absorption of focusedlaser light during laser etching disrupts intermolecular bonds in theilluminated material, fracturing or vaporizing the material. Based onthe depth of penetration of the light, which is a function of theabsorption of the material at the wavelength of the laser, theinter-molecular bond strength, the power of the laser, the laser cuttingspeed, and the spot size, laser etching can be used either to etch apattern into the release agent layer or to cut through the release agentlayer and the backing, e.g., to separate a long strip into separatetapes, e.g., bandages.

In an alternative embodiment, the release agent layer is micro-patternedvia mechanical abrasion, e.g., using sandpaper, to create micro-scaledivots in the release agent layer. While micro-patterning via laseretching creates more regularly spaced features in the patterned releaseagent layer, mechanical abrasion is a more readily scalable process, andhas the further advantage that it does not cause significant localizedheating of the release agent layer or the backing.

The release agent layer may also be patterned via chemical etching,reactive ion etching, gravure roll coating, stamping, photo-thermalablation, electron beam lithography, or another patterning method. Therelease agent layer may be patterned via a continuous process or a batchroll-to-roll process. In some instances, during patterning of therelease agent layer, full thickness cuts are made through the backing tocreate porosity in the backing.

In some examples, the release agent layer may be formed of two differentspecies that spinodally decompose or otherwise phase separate (e.g., amulti-component self-assembled monolayer). For example, two differentpolymers (referred to as polymer A and polymer B) may be dissolved in acommon solvent or co-solvent system, or heated, and then cast into afilm. Provided that polymers A and B phase separate during theirtransition from the liquid to solid phase, domains of one polymer (e.g.,polymer A) will form in the other polymer (e.g., polymer B). If polymersA and B have different adhesion properties with respect to the adhesivelayer, the relative surface area and arrangement of the two polymersaffects the peel and shear adhesive properties. In some instances, morethan two polymers can be used to tune the properties of the releaseagent layer. In other instances, polymers containing more than onemonomer, such as diblock and triblock copolymers, can also phaseseparate on solidification. Examples of polymer blends that phaseseparate include, but are not limited to polyacrylic acid andpolystyrene, polyethylene glycol and polystyrene,poly(glycidylmethacrylate) and polystyrene, andpoly[1,6-bis(p-carboxyphenoxy)hexane] andpoly(D,L-lactide-co-glycolide). Additionally, if added in sufficientquantity non-polymeric additives can also phase separate and producedomains in polymeric films.

The patterned release agent layer 210 is cleaned and adhesive layer 204is applied onto release agent layer 210 (step 604). In one example,adhesive layer 204 is applied via solvent casting onto release agentlayer 210 followed by solvent evaporation, which may be accelerated byheating. In another example, a transfer film of adhesive is formedseparately, and the pre-formed, solvent evaporated transfer film isphysically transferred onto release agent layer 210.

Adhesive layer 204 is formed of a pressure sensitive adhesive. Incertain examples, adhesive layer 204 can be formed of an acrylic-basedadhesive. However, any suitable adhesive having sufficient adhesion tothe target substrate (e.g., skin) and, if required, appropriatebiocompatibility characteristics, can be used. Release agent layer 210is formed of a material having low adhesion or anti-adhesion to adhesivelayer 204 and high adhesion to backing 208. Thus, for instance, asiloxane-based release agent may be used with an adhesive layer based onacrylic acid or on a hydrocolloid composition. A fluorosilicone-basedrelease agent may be used with a silicone-based backing.

In some embodiments, quick-release tape 200 is produced by aroll-to-roll coating process, enabling the quick-release tape to beproduced by readily scalable processes. For instance, an appropriatethickness of solvent-free or dissolved adhesives (e.g., acrylate orhydrocolloid- or silicone-based adhesives) are applied directly to therelease agent layer coated backing. The adhesive is cured in place(e.g., by ultraviolet (UV) exposure or heat) or is thermally evaporated,yielding a pressure sensitive adhesive layer on the release agent layercoated backing. In some cases, if the backing or release agent layer isformed of a material that would be chemically or mechanically affectedby the adhesive application and/or curing process, a transfer film isused to transfer already-cured adhesive onto the release agent layercoated backing. In this example, the adhesion between the transfer filmand the adhesive layer is less than the adhesion between the adhesivelayer and the release agent layer coated backing.

More generally, in some embodiments, the quick-release tapes describedherein alter only the support layer/backing-adhesive interface; theskin-adhesive interface and the backing material remain unchanged ascompared with standard medical tapes. Thus, the structure of thequick-release tapes is widely applicable to a variety of adhesives andbacking materials, including, for instance, standard adhesives for whichthe skin irritability profiles have already been well characterized.

Alternative Compositions of the Quick-Release Tapes

In alternative embodiments, the release agent layer is a uniform layerthat is environmentally sensitive and degrades when in the presence of acue. The degradation of the release agent layer allows for easy removalof the backing from the adhesive layer.

For instance, an enzyme-degradable release agent layer is formed ofco-polymers synthesized from low molecular weight, biocompatible,non-degradable pre-polymers and peptides or oligosaccharides connectedby enzyme-labile linkers. Such a release agent layer may be appliedusing a variety of methods, such as roll coating, spin coating,evaporation, or other deposition methods. Exemplary pre-polymersinclude, for instance, polyethylene glycol, polyurethanes, matrixmetalloproteinase sensitive hydrogels, esterase sensitive materials(including cross-linked, uncross-linked, and self-assembled gels), andcellulose derivatives.

When an enzyme solution (e.g., a peptidase or amylase solution) isapplied, e.g., as a liquid or via an applicator, such as a cotton swab,the peptide bonds or glycosidic bonds in the release agent layer arebroken, yielding low molecular weight constituents with littlemechanical strength. In some cases, peptidases can be applied to cleavepeptide sequences that have been introduced into the polymer backbone.For instance, chymotrypsin may be used to cleave tyrosine-tyrosinelinkages. In these embodiments, peptide sequences are covalentlyattached within thermoplastic polymers as cleavage sites. In thepresence of the enzyme (i.e., the peptidase), the peptide bonds arebroken. As a result, the average molecular weight of the polymer chainsis reduced, weakening the mechanical linkage between the backing andadhesive layers provided by the polymer layer. In some cases, thepolymer forming the release agent layer is a solid; upon addition of theenzyme, the polymer release agent layer is liquefied. Increasing theenzyme concentration, among other factors, can increase the speed of thedegradation.

In another example, the release agent layer is a pH sensitive layer. ApH sensitive layer can be fabricated, for instance, via layer-by-layerdeposition of oppositely charged macromolecules; or by coating thebacking with a pH-sensitive thermoplastic polymer. For instance, the pHsensitive release agent layer may be formed from pH sensitivepolyacrylate or gelatin derivatives. In these examples, when the releaseagent layer is wet with de-ionized water (e.g., as may occur duringwashing or long-term placement in an incubator environment), the releaseagent layer remains intact. A change in pH, such as a change of 0.25,0.5, or 1, causes the release agent layer to dissolve. In some cases,the pH sensitive layer includes a polyanion and a polycation that arewater insoluble and dissolves in an ionic solution.

In an alternate example, the release agent layer is photodegradable. Forinstance, the release agent layer is formed of a polymer that rapidlydegrades into low molecular weight components when exposed to light of aparticular wavelength. Photodegradable monomers include but are notlimited to, for example, tert-butyl-4-vinylphenyl carbonate. Thedegraded release agent layer loses mechanical strength, allowing thesupport layer to be easily removed.

In some examples, the release agent layer swells, reducing itsmechanical integrity and thus the force sufficient for removal of thesupport layer, in the presence of certain solvents or other materials.For instance, the release agent layer may be formed of a material thatswells in the presence of saline or isopropanol, such as, for instance,cellulose derivatives, polyurethanes and hydrogels.

In another example, either the release agent layer or the backing isformed of a shape memory material made up of fibrillar structures. Whena shape memory polymer is exposed to a temperature above its transitiontemperature, it reverts to its “locked-in” shape. In doing so, thefibrillar structures in the material change from adhesive tonon-adhesive, which would facilitate removal of the support layer of thequick-release tape. An exemplary shape memory material is described in“A Path to Strong and Reversible Dry Adhesives” (Advanced Materials,22:2125-2137, 2010), the contents of which are incorporated herein byreference.

In some examples, release agent layer 210 can include a releasemodifying agent such that the release agent layer 210 is anti-adhesiveto certain types of adhesives, such as acrylic adhesives. For instance,release agent layer 210 can be formed of a silicone-based material or afluorosilicone-based material and modified with a resin, such as asiloxane resin. Examples of these materials can be found, for example,in U.S. Pat. No. 5,696,211 and in PCT Publication No. WO2012128919, theentire contents of both of which are incorporated herein by reference.

In another alternative embodiment, the support layer includes only asingle layer. For instance, the support layer is formed of a polymerthat has poor interfacial or normal adhesion (e.g., the adhesion in adirection perpendicular to the interface) with the adhesive layer. Onepotential materials combination is a silicone support layer with anacrylate adhesive; and alternative combination is a fluorosiliconesupport layer with a silicone-based adhesive.

Another example of a single-layer support layer is a support layerformed of a directional adhesive. For instance, the support layer may beformed of a uni-directionally stretchable fabric embedded in silicone.When shear is applied perpendicular to the stretch axis in theinextensible direction of the fabric, the layer adheres strongly to theadhesion layer. When the fabric is stretched along the elastic axis, thelayer releases with little force. An exemplary directional adhesive isdescribed in “Looking Beyond Fibrillar Features to Scale Gecko-LikeAdhesion” (Advanced Materials, 24(8)1078-83, 2012), the contents ofwhich are incorporated herein by reference.

In another embodiment, micro- or nano-patterning of the support layer,rather than a release agent layer, can be used to create a directionallyanisotropic adhesive. For instance, micro-scale pillars with angledfeatures have demonstrated directionally dependent adhesion. Suchpillars would enable strong shear adhesion (e.g., adhesion in the planeof the interface) between the support layer and the adhesive layer, butwould allow the support layer to be peeled with low force. Exemplarydescriptions of the structure and fabrication of such pillars can befound in “Directional adhesion of gecko-inspired angled microfiberarrays” (Applied Physics Letters, 93:191910-12, 2008) and “Anontransferring dry adhesive with hierarchical polymer nanohairs” (PNAS,106(14)5639-5644, 2009), the contents of both of which are incorporatedherein by reference.

Mechanical Properties of the Quick-Release Tapes

The quick-release tapes described herein are quickly and easilyremovable from a substrate without inflicting damage to the substrate.To achieve such removal, the adhesion between the adhesive layer and thesupport layer is tuned to be less than the adhesion between the adhesivelayer and the substrate. As a result, when the quick-release tapes arepeeled from the substrate (e.g., by applying a normal forceperpendicular to the interface between the tape and the substrate), thesupport layer is peeled away from the adhesive layer, leaving theadhesive layer on the substrate while imparting minimal force on thesubstrate. That is, by designing the quick-release tapes to fail at aninternal interface (i.e., between the adhesive layer and the supportlayer), the stress and strain experienced by the substrate can beminimized, reducing the potential for damage to the substrate.

Referring again to FIG. 3, the micro-patterned release agent layerincludes regions of high adhesion and regions of low adhesion oranti-adhesion between the support layer and the adhesive layer. Withingaps 300, the adhesive layer 204 contacts and adheres to backing 208;that is, the adhesion between the adhesive layer and the support layeris high in gaps 300. Where release agent layer 210 is present, therelease agent layer contacts adhesive layer 204; these regions have lowadhesion or anti-adhesion.

The overall adhesion between adhesive layer 204 and support layer 206 istuned by the relative fraction of highly adhesive regions to lower,non-, or anti-adhesive regions. That is, the adhesion between adhesivelayer 204 and support layer 206 can be tuned by varying the percent areaof exposed backing (e.g., x_(lines) or x_(grid lines), in the case of alaser etched release agent layer). To ensure that support layer 206 canbe removed without removing adhesive layer 204 from substrate 202, theadhesion between adhesive layer 204 and support layer 206 is controlledvia the geometry of the micro-patterned release agent layer 210 to beless than the adhesion between adhesive layer 204 and substrate 202.

The adhesion between adhesive layer 204 and support layer 206 can beadjusted as high as a standard medical tape having the given combinationof adhesive and backing materials by causing 100% of backing 208 to beexposed to adhesive layer 204 (i.e., by removing all of release agentlayer 210). Similarly, the adhesion between adhesive layer 204 andsupport layer 206 can be adjusted as low as an extremely weak adhesiveby allowing none of backing 208 to be exposed to adhesive layer 204(i.e., by removing none of release agent layer 210). That is, by varyingthe percent area of exposed backing, the adhesion of adhesive layer 204to support layer 206 can tuned to any value between the upper bound ofthe adhesion of the pure polymer backing to adhesive layer 204 and thelower bound of adhesion of the fully release agent layer coated backingto adhesive layer 204.

In addition to achieving low adhesion at the interface between adhesivelayer 204 and support layer 206, quick-release tape 200 exhibits highshear strength at both the interface between adhesive layer 204 andsubstrate 202 and the interface between adhesive layer 204 and supportlayer 206. Furthermore, with the choice of a sufficiently strongadhesive, a high normal adhesion between adhesive layer 204 andsubstrate 202 can be achieved. High shear strength and normal adhesionto substrate 202 help to maintain device fixation, for instance, duringmotion of skin relative to the adhesive layer of the tape.

When quick-release tape 200 is peeled from substrate 202, the geometryof release agent layer 210 and the interfacial chemistry and rheology ofadhesive layer 204 govern crack propagation. At each juncture of backing208, release agent layer 210, and adhesive layer 204 (e.g., a juncture302), a propagating crack can either continue to propagate along thesupport layer-adhesive layer interface, leaving residual adhesive on thesubstrate; or along the adhesive layer-substrate interface, pulling theadhesive off of the substrate. By closely spacing laser etched lines inrelease agent layer 210, crack propagation can be forced along thesupport layer-adhesive layer interface, thus causing residual adhesiveto remain on the substrate.

As shown in FIG. 7A, residual adhesive 204 can be removed from substrate202 by pushing and rolling the adhesive, possibly because a sufficientthickness of adhesive has been left on the surface. However, pushing androlling the adhesive is often not suitable for fragile skin. In somecases, leaving residual adhesive on the skin may be safer than removalof the adhesive. If left tacky, however, the residual adhesive couldpotentially adhere to other surfaces (e.g., clothing or bedding), againintroducing the possibility of skin damage.

As shown in FIG. 7B, a powder, such as talcum powder, can be applied toresidual adhesive 204. Once fouled with a layer of powder (depicted as alayer 700), residual adhesive 204 no longer exhibits tack. Furthermore,the powder-fouled residual adhesive 700 does not recover its tackinesswhen exposed to water, which is an important characteristic of a tapethat is to be used in a humid neonatal incubator environment or, moregenerally, in a medical setting in which washing with water occurs.

In medical settings, the ability to affix, remove, and re-affix orreposition devices with adhesives is important. A second medical tapecan be applied over the washed, powder-fouled residual adhesive 700; thesecond tape adheres to the powder-fouled residual adhesive 700 withsubstantially the same force with which it would have adhered to thesubstrate directly. That is, the washed, powder-fouled residual adhesiveserves as a suitable attachment site if reattachment of a new tape isnecessary before the residual adhesive has sloughed off or otherwisebeen removed.

Applications and Uses of the Quick-Release Tapes

FIGS. 8A-8C show an example of quick-release tape 200 used to affix anendotracheal (ET) tube 800 to skin 802. Intact quick-release tape 200strongly secures tube 800 to the skin due to the mechanical cohesionprovided by the backing (FIG. 8A), the shear strength of the intratapeinterfaces, and the normal adhesion of the adhesive layer to skin 802.Once support layer 206 is removed (FIG. 7B), the cohesive strength ofthe residual adhesive 204 determines the degree of device fixation.Because adhesives do not generally have a high cohesive strength, tube800 can easily be removed (FIG. 8C), leaving a gap 804 in residualadhesive 204.

Referring to FIG. 9, quick-release tapes can be provided in a roll 900.To ensure that adhesive layer 204 does not stick to the back side ofbacking 208 when the tape is formed into a roll, an anti-adhesive coverlayer 902 is placed on the side of adhesive layer 204 opposite releaseagent layer 210 such that when rolled up, cover layer 902 contactsbacking 208. Cover layer 902 is designed and selected such that theadhesion between adhesive layer 204 and support layer 206 is greaterthan the adhesion between adhesive layer 204 and cover layer 902. Forinstance, cover layer 902 may be formed of the same material as releaseagent layer 210, but with no pattern, thus preventing any of the backside of backing 208 from being exposed to adhesive layer 204 andensuring a low adhesion between adhesive layer 204 and the back side ofbacking 208.

Referring to FIGS. 10A and 10B, a quick-release tape 250 includes anadhesive layer 254 and a support layer 256. A first image 262 isdisplayed on the support layer 256 (FIG. 22A), such that when thequick-release tape 250 is first applied to a substrate (e.g., as amedical bandage), the first image 262 is shown. When support layer 256is removed (FIG. 22B), a second image 264 displayed on adhesive layer254 is shown. The images 262 and 264 are not limited to the imagesdepicted in the Figures, but may be any letters, symbols, designs, orother images, and may include a single color or multiple colors.

The structure of the quick-release tapes described herein is not limitedto use with a tape, but can apply equally to any medical adhesive,including, e.g., bandages, adhesive electrodes, adhesive temperatureprobes, and adhesive medical devices.

EXAMPLES

The invention is further described in the following examples, which donot limit the scope of the invention described in the claims.

The following examples generally show comparative strengths of varioustypes of tapes, demonstrating that the quick-release tapes describedherein have a peel strength lower than that of conventional tapes. Theexamples further demonstrate that the morphology of the release agentlayer of the quick-release tapes described herein affects the adhesionof the tape. The use of such quick-release tapes in affixing anendotracheal (ET) tube to a substrate is also demonstrated. In addition,the implications of leaving residual adhesive on the substrate aftertape removal are explored.

Peel force, probe tack, and device removal force may change as afunction of removal speed. In the specific examples described below,peel tests were performed at a removal rate of 5 mm/s as specified bythe Pressure Sensitive Tape Council (PSTC). Probe tack tests wereperformed such that a 1 cm diameter flat, aluminum probe contacted theadhesive layer at a target force of approximately 3 N for 30 seconds andwas then withdrawn at a rate of 1 mm/s. As exemplary devices affixed byquick-release tape, uncuffed neonatal endotracheal tubes were pulledfrom the surface at a rate of 5 mm/s. However, alternative testingmethodologies exist and may also be applied to test the properties ofthe quick-release tape described herein.

Example 1—Preparing a Multi-Layer Quick-Release Tape

A quick-release tape was formed by coating a siloxane-based releaseagent (Dow Corning Syl-Off® SL 9106 Coating, Auburn, Mich.) onto a 50 μmthick PET backing sheet using a Euclid Coating Systems Single RollCoater (Bay City, Mich.). To cure the two-part release agent, the coatedbacking sheets were placed in a drying oven for 5 minutes at 180° C.

To micro-pattern the release agent layer, a pattern was drawn usingCorelDRAW® Graphics Suite X5 (Mountain View, Calif.). The pattern wasetched into the release agent layer using a 30 Watt VersaLASER® VLS 2.3(Universal® Laser Systems, Scottsdale, Ariz.) with the laser cuttingspeed set to 100%, the power set to 10%, and the pulses per inch (PPI)set to 1,000 to make partial thickness cuts that extended about 20 μminto the backing. The patterned sheets were then cut into strips of tapeusing the VersaLaser® with the power set to 50% and the other settingsmaintained as above. The strips were cleaned in 70% ethanol to removeresidual particles.

Referring to FIGS. 11A-11B, after release agent layer micro-patterning,elemental analysis was performed by energy-dispersive spectroscopyanalysis to confirm the removal of release agent in the desired regionsusing a Zeiss Ultra 55 field emission scanning electron microscope (CarlZeiss AG, Oberkochen, Germany) equipped with energy-dispersivespectroscopic elemental analysis. Carbon, oxygen, and silicon levelswere quantified within laser etched lines and between the lines. Therelease agent layer coated region (FIG. 11A) shows higher siliconcontent relative to carbon and oxygen than the etched lines (FIG. 11B),indicating that the siloxane-based release agent layer is intact. Theetched lines, in contrast, display low silicon content, indicative of aPET surface (i.e., the backing) with negligible residual siloxanerelease agent.

Surface profilometry analysis of the patterned release agent layer, forinstance as shown in FIGS. 4A-4D and FIG. 5, was performed using aTencor P-10 Surface Profilometer (KLA-Tencor, Milpitas, Calif.) equippedwith a 2 μm radius diamond tipped stylus.

An adhesive layer was applied to the patterned release agent layer bysolvent casting pressure sensitive adhesive (GELVA® GMS 2999, CytecIndustries Inc., West Paterson, N.J.) and heating at 60° C. toaccelerate solvent evaporation. In alternative embodiments, a transferfilm of adhesive can be formed (Syntac Coated Products, New Hartford,Conn.) and physically transferred onto the patterned release agentlayer.

Example 2—Tape Removal from a Paper Substrate

Referring to FIGS. 12A-12B, to experimentally illustrate the concept ofdamage free removal of the quick-release tape, strips of quick-releasetape 1200, conventional paper-backed medical tape 1202 (3M™ Micropore™Medical Tape), and conventional plastic-backed medical tape 1204 (3M™Transpore™ Medical Tape) were affixed to colored origami paper 1206taped to a laboratory bench 1208. To ensure even fixation, the tapeswere applied using a 10 pound hand roller (ChemInstruments, Fairfield,Ohio). One end of each strip of tape was wrapped around a metal ruler.To simulate an emergency response scenario, the metal ruler was rapidlypulled (about 5 cm/s), peeling all of the tape strips from the paper.

The conventional tapes 1204 and 1206 rip the colored portion of theorigami paper, exposing the underlying white paper. Quick-release tape1200 does not damage the origami paper, and leaves behind residualadhesive on the surface of the paper.

Origami paper can be considered a proxy for sensitive neonatal skingiven that it is easily damaged during rapid removal of conventionaltape. In particular, under the conditions of the test, removal ofconventional tapes causes tearing of the superficial layer (the coloredportion of the origami paper) from the deep layer (the underlying whitepaper), akin to stripping of skin by removal of medical tape. Given thatthe quick-release tape does not induce tearing when removed from theorigami paper under the same conditions, it can be inferred that thequick-release tape transmits significantly less force to the underlyingsubstrate than do conventional tapes.

Example 3—Tape Removal from a Stainless Steel Substrate

Ninety degree peel tests were conducted under conditions prescribed bythe Pressure Sensitive Tape Council (PSTC) to determine the average andmaximum peel forces of various types of tape from a stainless steelsurface. A two-layer tape formed of poly(ethylene terephthalate) (PET)backing with a solvent cast strong acrylic adhesive was tested todetermine the strength of the acrylic adhesive that is used in theexemplary quick-release tapes tested in other examples described herein.Note that this tape, referred to as “PET tape,” does not include arelease agent layer. The PET tape was compared to commercially availableplastic- and paper-backed medical tapes (3M™ Transpore™ Medical Tape and3M™ Micropore™ Medical Tape, respectively). In addition, a tape with aweak adhesive designed for gentle removal from neonates (NeoFlex™ tapefor use in neonatal environments, NeoTech) was tested.

Referring to FIG. 13A, to conduct the tests, a strip of tape 1300 wasadhered to a polished 304 stainless steel plate 1202. The tape waspeeled from the stainless steel plate at a 90 degree angle at a rate of5 mm/s using an ADMET eXpert 7600 single column mechanical testerequipped with a 90 degree peel testing fixture (Norwood, Mass.). Foreach tape, the average peel force and the maximum peel force weredetermined. The average peel force was calculated by averaging peelforce data (N=3) acquired at a peel distance of 5-10 cm. The maximumpeel force was determined by identifying the maximum force reachedduring the peel test.

Referring to FIGS. 13B and 13C, the average and maximum peel forces forthe PET tape are more than twice the peel forces of commerciallyavailable plastic- and paper-backed tapes, and more than an order ofmagnitude greater than the peel forces of NeoFlex™.

These results demonstrate that the adhesive that is used for theexemplary quick-release tapes tested in the examples that follow is astrong adhesive. High adhesive strength is not required for all neonatalmedical tape functions, nor, more generally, is it necessary for thequick-release tapes described herein. However, the examples in thisdisclosure utilize a strong adhesive to emphasize that rapid,damage-free removal of the quick-release tapes can be achieved withoutsacrificing adhesive strength.

In Example 3 (and in all subsequent examples), data were compared byone-way analysis of variance (ANOVA) with post hoc Tukey's HonestlySignificant Difference in means with the Bonferroni correction appliedas appropriate (AnalystSoft, Alexandria, Va.). All plots show N=3; errorbars indicate the mean plus one standard deviation; the results havep-values as follows: *p<0.05, **p<0.01, ***p<0.001.

Example 4—Tape Removal from Skin

Referring to FIGS. 14A-14C, 90 degree peel tests were conducted for tape1400 peeled from medial ventral forearm skin 1402. The conditions of thepeel tests and the tapes tested are as described in Example 3.

The trends in peel force from forearm skin match the trends observed inthe stainless steel peel tests of Example 3. However, the average andmaximum peel forces for each type of tape are lower from forearm skinthan from stainless steel, which is consistent with the knownperformance of pressure-sensitive adhesives on skin versus stainlesssteel.

Example 5—Effect of Macro-Scale Surface Area of Backing-AdhesiveInteraction

Peel tests were conducted to determine the effect of varying, on themacro-scale, the percent area of exposed backing on the adhesion of thequick-release tapes.

Referring to FIG. 15A, strips of release agent coated PET 1500 werelaser cut to widths of 25%, 50%, 75%, and 100% of the width of a 25 mmwide PET backing. Each laser cut strip was placed in the center of a PETbacking 1502 and affixed to the backing using a 10 pound hand roller. Anacrylic-based adhesive layer was applied as described above to form amacro-scale patterned quick-release tape. The tapes were peeled at 90degrees from a polished stainless steel plate 1504 while monitoringforce as a function of peel distance. The average and maximum peelforces were determined as a function of the percentage of exposed PET(i.e., the PET fraction as opposed to the release agent fraction).

Referring to FIGS. 15B and 15C, 100% PET (i.e., a backing with norelease agent layer) showed strong adhesion to the adhesive layer, whilea release agent coated PET (0% PET) exhibited negligible adhesion to theadhesive layer.

Both average and maximum peel forces exhibited an inverse cubic functiondependence of peel force on the surface area of interaction between PETand the adhesive layer. Without wishing to be bound by theory, theseresults suggest that van der Waals forces, as predicted by the Derjaguinapproximation (F˜1/D³) dominate the interaction between the adhesivelayer and the release coated backing, rather than chemical bonding orpolymer chain interpenetration.

Example 6—Effect of Laser Etched Release Agent Layer on Adhesion

Peel tests were conducted for quick-release tapes having release agentlayers micro-patterned via laser etching to determine the effect of linespacing on adhesion. Release agent layers coated onto strips of PETbacking were patterned using laser etching as described above to form100 μm wide lines spaced (center-to-center) by 0.5 mm, 1 mm, 2 mm, 4 mm,and 8 mm. An acrylic acid-based adhesive was solvent cast onto eachpatterned release agent layer to form a tape strip. The tape strips wereadhered to a stainless steel substrate and a 90 degree peel test wasconducted as described above to measure the average and maximum peelforce for each tape.

Referring to FIGS. 16A-16B, lines spaced by 0.5 mm provide a modestincrease in average and maximum peel force over more widely spaced linesand over PET coated with unpatterned release agent layer (shown in FIGS.15B-15C).

Theoretical peel forces were calculated as a function of the percentarea of exposed backing (x_(lines)) according to the inverse cubicfunction, as suggested by the curve fit for the macro-scale experimentdescribed in Example 5. The experimental average and maximum peel forcesfor the micro-patterned tape strips are in good agreement with thetheoretical peel forces (shown as a dashed line), confirming theprediction that the percent area of exposed backing dictates theadhesion between the support layer and the adhesive layer.

Peel tests were also conducted for quick-release tapes having releaseagent layers micro-patterned with grid lines to determine the effect ofgrid line spacing on adhesion. Release agent layers coated on strips ofPET backing were laser etched to form 100 μm wide grid lines spaced(center-to-center) 0.5 mm, 1 mm, 2 mm, 4 mm, and 8 mm. An acrylic acidadhesive layer was solvent cast onto each patterned release agent layerto form a tape strip. The tape strips were adhered to a stainless steelsubstrate and a 90 degree peel test was conducted as described above tomeasure the average and maximum peel force for each tape.

Referring to FIGS. 17A-17B, as with the laser-etched lines, square gridlines spaced by 0.5 mm provide a modest increase in average and maximumpeel force over more widely spaced grid lines. The experimental averageand maximum peel forces again are in good agreement with theoreticalpeel forces (shown as a dashed line) calculated according to the inversecubic function.

For a given line spacing, grid lines provide increased exposure of thePET backing to the adhesive layer as compared to lines (i.e., x_(lines)versus x_(grid lines)). Thus, as might be expected, grid lines spaced by1 mm result in peel forces similar to peel forces of lines spaced by 0.5mm, as these two geometries offer roughly equivalent amounts of exposedPET. Similarly, the 0.5 mm spaced grid lines cause a peel force ofapproximately double the peel force of the 0.5 mm spaced lines, becausea greater amount of PET is exposed to the adhesive by the grid lines.

Referring to FIG. 17C, the mechanism of adhesion of a quick-release tapehaving release agent layers micro-patterned with 1 mm spacedlaser-etched grid lines etching was studied using high-speed (100 Hz)video analysis of crack propagation. Peel tests (0.5 mm/s peel rate)were conducted and the rate of crack propagation was determined.Analysis of video images revealed that the rate of crack propagation wasslower within regions where the adhesive layer contacts the PET backingand faster within regions where the release agent layer contacts the PETbacking

High-speed video was captured using Dino-Lite® Digital Microscope Prousing DinoCapture 2.0 software for image analysis. Individual frameswere analyzed to track the propagation of the crack front as a functionof time. Crack propagation rates perpendicular to the peel directionacross release agent coated surfaces and within laser-etched lines wereaveraged separately to arrive at average crack propagation speeds foreach region.

Example 7—Effect of Mechanical Abrasion of Release Agent Layer onAdhesion

Referring to FIGS. 18A-18B, release agent layers coated on PET backingswere mechanically abraded using sandpaper to create micro-scale divotsin the release agent layers. An acrylic-based adhesive was solvent castonto each mechanically patterned release agent layer to form a tapestrip. Each tape strip was adhered to a stainless steel substrate and a90 degree peel test was conducted to measure the average and maximumpeel force.

The root mean square (RMS) average surface roughness created bysandpaper roughening, as measured via two-dimensional surfaceprofilometry, of the release agent layer decreases with decreasingparticle size, indicating that the morphology of the release agent layeris controllable via appropriate selection of sandpaper grit.

Release agent layers patterned with 120 grit sandpaper (115 μm averageparticle diameter) and 240 grit sandpaper (53 μm average particlediameter) resulted in similar peel forces (i.e., similar adhesion).While the grit is more densely packed on the 240 grit sandpaper than itis on the 120 grit sandpaper, the grit layer on the 120 grit sandpaperis thicker. Therefore, the 120 grit sandpaper creates deeper divots thanthe 240 grit sandpaper, likely causing similar amounts of PET to beexposed to the adhesive layer. The adhesive is sufficiently amorphousand viscous to be able to fill the micro-scale divots produced bysandpaper roughening of the release agent layer.

400 grit sandpaper (23 μm average particle diameter) results in a peelforce that is significantly higher than the peel force associated withthe larger grit sandpapers. Indeed, the peel force of tapes patternedwith 400 grit sandpaper was so high that portions of the adhesive wereremoved from the stainless steel plate during the peel test. The averageparticle radius of 40 grit sandpaper (11.5 μm) is an order of magnitudelarger than the thickness of the release agent layer (0.5-0.8 μm). Thus,abrasion with 400 grit sandpaper readily removes a large amount of PET,exposing a significant fraction of the PET backing to the adhesivelayer. Without wishing to be bound by theory, it is expected that thelarge contact area between the PET backing and the adhesive layerstabilizes the interface between the adhesive layer and the supportlayer, causing the fracture zone to transition from that interface tothe adhesive layer-substrate interface.

Example 9—Anisotropic Adhesion

The foregoing examples demonstrate that the adhesion of a quick-releasetape can be controlled via structural manipulation of the release agentlayer. However, in addition to the ability to achieve a target adhesion,it is desirable for a quick-release tape to have the ability to securelyaffix a device to a substrate. To demonstrate this functionality of thequick-release tape, a neonatal endotracheal (ET) tube, which is a tubecommonly used to support respiratory function, was adhered to asubstrate using a variety of medical tapes. The shear and normaladhesion of each tape to the substrate were measured.

An uncuffed neonatal ET tube 1900 (Smiths Medical, Norwell, Mass.) wasaffixed to a polished stainless steel plate 1904 by each of aquick-release tape having a sandpaper abraded release agent layer,commercially available plastic- and paper-backed medical tapes (3M™Transpore™ Medical Tape and 3M™ Micropore™ Medical Tape, respectively);and NeoFlex™, a tape designed specifically for easy removal fromneonates.

Referring to FIG. 19A, to measure shear adhesion, one end of the ET tubewas pulled parallel to the surface of the stainless steel plate andalong a longitudinal axis of the tube at a rate of 5 mm/s whilerecording shear force as a function of pull distance. The maximum shearforce was determined by identifying the maximum force reached duringeach test.

Referring to FIG. 19B, with the support layer in place, thequick-release tapes performed better than standard plastic- andpaper-backed medical tapes, exhibiting higher average maximum shearforce than both commercially available tapes. The difference in maximumshear force between intact quick-release tapes and the tested commercialtapes may be due to the use of a less aggressive adhesive in thecommercial tapes. Quick-release tapes with the backing in place alsosignificantly outperformed NeoFlex™.

Once the support layer is removed from the quick-release tapes, only thecohesive strength of the adhesive layer holds the ET tube in place.Cohesive failure involves minimal shear force; a drop of 83% in maximumshear force is measured compared to the shear force measured for intactquick-release tapes (i.e., a device fixation shear adhesioncharacteristic of the quick-release tape is reduced by removal of thesupport layer). The adhesive layer alone exhibits a similar averagemaximum shear force as NeoFlex™, which is designed specifically to havelow adhesive strength to facilitate easy removal in a neonatal caresituation.

Referring now to FIG. 20A, to test device fixation in the normal (orperpendicular) direction, one end of the ET tube was lifted upwards andaway from the stainless steel plate at 5 mm/s at a 90 degree angle untiladhesive bond failure occurred. The force was continually monitoredduring the test. The maximum peel force was determined by identifyingthe maximum force reached during each test.

Referring to FIG. 20B, intact quick-release tapes exhibited the highestmaximum normal peel force, followed by commercial plastic- andpaper-backed medical tapes. Neoflex™ and the residual adhesive from thequick-release tapes demonstrated the lowest normal peel forces. Inparticular, after removal of the support layer of the quick-releasetapes, the residual adhesive exhibited a maximum normal peel force 93%lower than intact quick-release tapes, demonstrating the ability ofquick-release tapes to facilitate quick, damage-free device removal.

By comparing the maximum shear performance (FIG. 19B) and the backingpeel force (FIGS. 16A-16B, 17A-17B, and 18A-18B) of the quick-releasetapes, the directional anisotropy in the adhesion between the adhesivelayer and the support layer is apparent. That is, intact quick-releasetapes provide significant adhesion in shear between the adhesive layerand the support layer. However, the support layer exhibits minimaladhesion to the adhesive layer when peeled normally from the adhesivelayer.

Example 10—Strength and Quantity of Residual Adhesive

Referring to FIG. 21A, a probe tack test was used to measure the maximumtensile strength adhering a probe to a surface. Probe tack tests wereused to characterize a layer of adhesive meant to correspond to residualadhesive remaining on a surface after removal of the support layer of aquick-release tape. An acrylic-based adhesive 2100 was adhered to a flataluminum sheet 2102. A 1 cm diameter aluminum probe 2104 was positionedparallel to the aluminum sheet and brought into contact with adhesive2000 at a speed of 1 mm/s until reaching a target compressive force of 3N. The probe was allowed to dwell in contact with the adhesive for 30seconds, and was then pulled away at a speed of 1 mm/s while monitoringthe tack force as a function of distance. The tensile fracture strengthof the adhesive was calculated as the maximum tack force measured duringeach test, normalized to the cross-sectional area of the probe (0.8cm²).

After the probe tack test of the adhesive was conducted, talcum (“baby”)powder (Johnson & Johnson, New Brunswick, N.J.) was applied to theexposed adhesive surface. A probe tack test was conducted on thetalc-fouled adhesive. The talc-fouled adhesive was then immersed inwater to remove the excess powder and dried; a probe tack test wasconducted on the washed, talc-fouled adhesive. Finally, a layer of thesame adhesive was applied directly onto probe 2104 and the probe tacktest was repeated on the washed, talc-fouled residual adhesive 2100.

Referring to FIG. 21B, pristine residual adhesive has an average tensilefracture strength of 4.1±0.3 N/cm². Fouling the residual adhesive withtalcum powder effectively de-tackifies the adhesive, reducing theaverage tensile fracture strength by 97.6%, to 0.01±0.1 N/cm².

Referring to FIG. 21C, washing away the excess talcum powder leaves athin layer of adhered talc particles, which is translucent and permitsvisual inspection of the underlying adhesive surface. A probe tack testto the washed (and dried), talc-fouled adhesive reveals a low tensilefracture strength on the order of the tensile fracture strength of theunwashed, talc-fouled adhesive, demonstrating that immersion in waterdoes not affect the talc-fouling of the residual adhesive.

A second adhesive adhered to the washed, talc-fouled adhesiveeffectively recovers the full tensile fracture strength (3.7±0.8 N/cm²)of the adhesive to the probe, demonstrating that the de-tackifiedadhesive can serve as a fixation point for future adhesives.

The residual adhesive remaining after removal of the backing or supportlayer of a tape can be quantified. Plastic- and paper-backed commercialmedical tapes (3M™ Micropore™ Medical Tape and 3M™ Transpore™ MedicalTape, respectively) were tested and compared with quick-release tapeshaving a 45 μm thick adhesive layer with a coating weight of either 1mil or 1.8 mil. The commercial medical tapes had an adhesive layerapproximately 25 μm thick. To measure the residual adhesive, 44 cmstrips of each tape were applied to pre-weighed pieces of aluminum foilusing a 10-pound hand roller (ChemInstruments, Fairfield, Ohio). Thetape strips were rapidly removed and the aluminum foil sheets weighed.The increase in mass of the aluminum foil was normalized to thecross-sectional area of the applied tape to yield values of residualadhesive mass per square centimeter.

Paper-backed tape left more residual adhesive per square centimeter thanplastic-backed tape. Patterned quick-release tapes left the entireadhesive layer on the aluminum foil, yielding more residual adhesivethan commercial tapes consistent with the coating weight of the adhesivelayer. In practice, this result suggests that when designing aquick-release tape an adhesive can be chosen having a desired adhesionto a target substrate and a coating thickness such that the mass perunit area of the residual adhesive can match that of a conventionalcommercial tape.

Example 8—Use of Commercially Available Materials for Quick-ReleaseTapes

PET is often used as a test backing for medical tapes (e.g., for theforegoing examples) and for transfer film construction. However, PET isa non-standard commercial medical tape backing. To demonstrate thegeneralizability of the approach of micro-patterning a release agentlayer to form a quick-release tape, a quick-release tape was constructedusing a commonly used commercial backing.

Commercially available plastic-backed tape (3M™ Transpore™ Medical Tape)has a backing composed of a proprietary polyethylene-ethylene vinylacetate blend (PE/EVA). PE/EVA tape was soaked in ethanol for 12 hoursto swell the adhesive layer, which was then removed with mechanicalabrasion, leaving only the backing. The PE/EVA backing was coated inrelease agent, which was micro-patterned via mechanical abrasion with240 grit sandpaper to expose regions of the underlying PE/EVA backing.The acrylic-based adhesive layer used in the foregoing examples wasdisposed on the release agent layer. 90 degree peel tests were conductedfor the original, commercially available PE/EVA backed tape (PE/EVA); aPE/EVA backed tape with an unpatterned release agent layer, and amicro-patterned PE/EVA tape to measure average and maximum peel forcesfor each tape from a stainless steel substrate.

Referring to FIG. 22, the micro-patterned release agent layer coatedPE/EVA tape exhibited a peel force between the values obtained forunpatterned release agent layer coated PE/EVA tape and commerciallyavailable PE/EVA tape. The overall trend of a decrease in peel forcewith an increase in percent area of exposed backing is maintained. Thatis, the support layer peel force can be tuned via micro-patterning ofthe release agent layer, regardless of the composition of the supportlayer (and specifically, the composition of the backing).

OTHER EMBODIMENTS

It is to be understood that while the invention has been described inconjunction with the detailed description thereof, the foregoingdescription is intended to illustrate and not limit the scope of theinvention, which is defined by the scope of the appended claims. Otheraspects, advantages, and modifications are within the scope of thefollowing claims.

What is claimed is:
 1. A quick-release tape comprising: a support layer,comprising: a backing layer, and a patterned release agent layerdisposed on a first side of the backing layer; an adhesive layerdisposed on the release agent layer; and an antiadhesive cover layer incontact with the support layer, wherein the tape is provided in a rollsuch that in the roll, the cover layer is in contact with a second sideof the backing layer, wherein an adhesion level between the cover layerand the support layer is less than an adhesion level between theadhesive layer and the support layer, and wherein the adhesion levelbetween the adhesive layer and the support layer is greater than anadhesion level between the adhesive layer and the cover layer.
 2. Thetape of claim 1, wherein when the adhesive layer is disposed on asubstrate, a first adhesion level between the adhesive layer and thesubstrate is greater than a second adhesion level between the adhesivelayer and the support layer.
 3. The tape of claim 1, wherein an adhesionlevel between the adhesive layer and the release agent layer is afunction of an angle of a force applied to an interface between theadhesive layer and the release agent layer.
 4. The tape of claim 1,wherein the release agent layer includes first domains and seconddomains.
 5. The tape of claim 4, wherein a first adhesion level betweenthe first domains and the adhesive layer is different from a secondadhesion level between the second domains and the adhesive layer.
 6. Thetape of claim 4, wherein an adhesion level between the adhesive layerand the support layer is a function of a fraction of the area of therelease agent layer composed of the first domains.
 7. A quick-releasetape comprising: a support layer, comprising: a backing, and a releaseagent layer disposed on a first side of the backing layer; an adhesivelayer disposed on the release agent layer; and an antiadhesive coverlayer in contact with the support layer, wherein the tape is provided ina roll such that in the roll, the cover layer is in contact with asecond side of the backing layer, wherein an adhesion level between thecover layer and the support layer is less than an adhesion level betweenthe adhesive layer and the support layer, wherein the adhesion levelbetween the adhesive layer and the support layer is greater than anadhesion level between the adhesive layer and the cover layer, andwherein the release agent layer is formed of a material having anadhesion level that changes in response to a stimulus.
 8. The tape ofclaim 1, wherein the cover layer is disposed on the adhesive layer.